Mercedes-Benz Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
416 Posts
Discussion Starter #1
Hi folks,

On the S420, the soft-close pump failed shortly after the electrical system melt-down. It had ceased closing 3 doors and the trunk, although 2 of the 3 doors was due to electrical lines that had melted through the hard plastic vacuum lines (they have been replaced).

I bought a salvaged pump off Ebay for about $150, which failed soon after installation. It stopped closing 1 door, then 2, then all 4 and the trunk. It was sold with no guarantee, so I'm SOL.

I've now bought a new unit from Autohaus, which is obviously pretty expensive, but appears (for the moment) to be operating correctly.

Now, I have 2 cores. They're functional but appear to be unable to create the correct vacuum pressure. If I pop the grey bottom off these things, are there guts in there I can clean, or replace with a remanufacturing kit? Or is that kind of a mystical, magical land that that is off limits to DIYers?

It would be nice to save one on the shelf for the S500 (it has ceased closing the driver's door twice in the last year, but resetting it from the fuse has it working properly again for months), and sell the other as a good remanufactured unit on Ebay.

Cheers! :eek:
 

·
Premium Member
Joined
·
1,463 Posts
Now, I have 2 cores. They're functional but appear to be unable to create the correct vacuum pressure. If I pop the grey bottom off these things, are there guts in there I can clean, or replace with a remanufacturing kit?
First, the soft close pump uses pressure to draw the doors in, not vacuum * common
misunderstanding due to the "vacuum" nature of the action obtained *.

Next, "correct" pressure, is the pressure needed to get the door into the
permanent close position of the door lock. The pump itself, has a preset
understanding (adjustment) of what that pressure should be, and that
does not have to be correct. If you door indeed lock completely,
but times out after 10s because the pump thinks the pressure should be higher,
an adjustment of the pump pressure should be done.

Take the pump apart. Theres different versions of guts in these, but
here is an image of mine, where you see the adjusting mechanism;


More images mine (a Coupe version);









There you can also see, that only one of the lines is
connected to the vacuum rail. * At the moment, not 100% sure
where that leads to, but I think it is for the retraction of
the handle, but again, thats handled by the other pump on
cars without soft close. Might also just be venting out
the air used in the pressure action? *

Good luck,
syljua
 

·
Registered
Joined
·
3,886 Posts
There are no rebuilding kits, some have found "hobby" motors and ground the shafts to work. I guess you learned your lesson on E-Bay. I have seen some companies offering to buy cores but probably dirt cheap, from mechanics.
How could you think of selling your home repaired, with no experience, as a rebuilt on E-Bay you would be just as bad as the other sellers!
This will tell you how the system works
http://w140repair.com/Closing_Assist_Pump.htm
 

·
Registered
Joined
·
26 Posts
:beerchugr:You have to use adjust wheel - the time pump need to work is 3 sec. everything else will made pump life shorter.Connect it as pump is open and try with closing trunk or door,it will save you time

I want to give a big THANKS to MikeJT, Syljua, and Peter Guenther. Their advices and posts give me proper point to solve my issues with S klasse.

Cheers mates!
:beerchugr:

ps. Firs pull fuse No 9 from fusebox in trunk, wait 10 sec,and connect in again and check if pump work, close trunk,door .. Adjustment of the pump is like - when pump discover that there is problem with some door or with trunk two times one after one,the pump shut off that line.

The picture I use is from theme of BENZBOSS.
 

Attachments

·
Registered
Joined
·
416 Posts
Discussion Starter #5
OK - wow, thanks for the feedback, that's very interesting, and very helpful! It seems that adjusting one or both of the pumps would have been a better next step than buying the new one. At least, I hope, the new one has fully corrected the issue for now. But, duly noted for whenever the pump craps out on the S500. :)

Thanks for the pics too, that's great. Straightforward enough.

Cheers...
 

·
Premium Member
Joined
·
4,660 Posts
OK - wow, thanks for the feedback, that's very interesting, and very helpful! It seems that adjusting one or both of the pumps would have been a better next step than buying the new one. At least, I hope, the new one has fully corrected the issue for now. But, duly noted for whenever the pump craps out on the S500. :)

Thanks for the pics too, that's great. Straightforward enough.

Cheers...
I should have Pete add a comment on my write-up. It has now been 6 years since I did the adjustment on my pump. It has not failed once to close any door or the trunk. The pressure shut off switch adjustment is a very robust fix.

Brett
 

·
Premium Member
Joined
·
769 Posts
I should have Pete add a comment on my write-up. It has now been 6 years since I did the adjustment on my pump. It has not failed once to close any door or the trunk. The pressure shut off switch adjustment is a very robust fix.

Brett
I have glanced at your write up before, but at second glance it finally makes sense. I will try the suggestions and see if I can fix mine. It times out after the first few tries. Thanks!!!!!!
 

·
Registered
Joined
·
3,886 Posts
I paid for one at 42K, in 97, MB replaced another at 62k in 01 at no charge, it started giving me problems at 85k in 05, did the tweek and it has not missed a lick. I mentioned the adjustment to MB and their story was "we cant" adjust it Mercedes will not authorize it, since it could blow the diaphrams! Evidently is is set for new locks /diaphrams/ and totally lubricated.
I did less than a half turn, so dont get over zealus.
 

·
Registered
Joined
·
680 Posts
I posted this in a separate post a few weeks ago, but a few more facts now. My driver door is the only one failing. Usually first thing in the morning pump is on for 9-10 sec's, short pause, then the vacuum phase for a few sec's.

Works for a couple more tries, then time for wife to use the car.

This evening, after wife brought car home from work, she turns car off and gets stuff out of car, I walk outside, check door, which usually is in failed mode. After pulling fuse, then shutting door, pump is on for 9-10 sec's (then pause, then vacuum phase, a few sec's), and I try it 4 more times, each one successful, but pump is only on for 4-5 sec's. I quit testing at that point, and drive car in garage.

Next night, same thing. Lather, rinse, repeat.

The longest pump time is always the first try of the morning, or evening, after a several hour rest.

Does this sound like a pump, or, a plastic line problem, or leaky seal at the pump where the line goes in ? Guess I could take a peek.
 
1 - 9 of 9 Posts
Top